Lift assist systems for motor vehicles

Abstract

Lift assist systems are provided for use with motor vehicle assemblies. An exemplary lift assist system may include features for reducing the rate at which a tailgate pivots open and reducing the amount of force required to pivot the tailgate closed.

What is claimed is: 
     
         1 . A vehicle assembly, comprising:
 a tailgate configured to pivot between a closed position and an open position; and   a lift assist system connected to the tailgate and including a torsion rod and a nitrogen gas strut,   wherein the lift assist system is configured such that, when the tailgate is pivoted from the open position to the closed position, the torsion rod applies a first force on the tailgate and the nitrogen gas strut applies a second force on the tailgate.   
     
     
         2 . The vehicle assembly as recited in  claim 1 , wherein the torsion rod extends between a first end that is rotatably attached to a support assembly and a second end that is fixedly attached to a clamp box. 
     
     
         3 . The vehicle assembly as recited in  claim 2 , wherein the support assembly includes a flange and a shaft that extends through the flange and rotates relative to the flange, and the first end includes an attachment sleeve that is configured to receive the shaft. 
     
     
         4 . The vehicle assembly as recited in  claim 2 , wherein the clamp box is secured to a lower wall of the tailgate. 
     
     
         5 . The vehicle assembly as recited in  claim 2 , wherein, when the tailgate is pivoted between the closed position and the open position, the second end does not rotate relative to the clamp box. 
     
     
         6 . The vehicle assembly as recited in  claim 1 , wherein the nitrogen gas strut includes a first end that is pivotably attached to a support assembly and a second end that is fixedly attached to a vehicle endwall. 
     
     
         7 . The vehicle assembly as recited in  claim 6 , wherein the vehicle endwall is a laterally extending surface of a vehicle sidewall. 
     
     
         8 . The vehicle assembly as recited in  claim 6 , wherein the second end is above a vehicle bumper. 
     
     
         9 . The vehicle assembly as recited in  claim 6 , wherein the support assembly includes a bracket, a support, a cup, a flange, and a bell crank. 
     
     
         10 . The vehicle assembly as recited in  claim 1 , wherein the nitrogen gas strut is mounted in an open area defined by a vehicle sidewall and an outer panel of a vehicle body. 
     
     
         11 . A vehicle assembly, comprising:
 a tailgate positioned between a first vehicle sidewall and a second vehicle sidewall, the tailgate configured to pivot between a closed position and an open position;   a torsion rod rotatably attached at a first end to the first vehicle sidewall and fixedly attached at an opposite, second end to a clamp box; and   a nitrogen gas strut pivotably attached at a first end to the tailgate and fixedly attached at an opposite, second end to a portion of the second vehicle sidewall.   
     
     
         12 . The vehicle assembly as recited in  claim 11 , wherein the first end of the torsion rod extends through a first side of the tailgate and is attached to a support assembly that is secured to the first vehicle sidewall. 
     
     
         13 . The vehicle assembly as recited in  claim 12 , wherein the support assembly includes a flange and a shaft that extends through the flange and rotates relative to the flange, and the shaft is received within an attachment sleeve of the first end. 
     
     
         14 . The vehicle assembly as recited in  claim 11 , wherein the second end of the torsion rod includes an attachment section that is received within a channel of the clamp box so that the second end does not rotate relative to the clamp box. 
     
     
         15 . The vehicle assembly as recited in  claim 11 , wherein the first end of the nitrogen gas strut is attached to a support assembly that is secured to the tailgate. 
     
     
         16 . The vehicle assembly as recited in  claim 15 , wherein the support assembly includes a bracket, a support, a cup, a flange, and a bell crank. 
     
     
         17 . The vehicle assembly as recited in  claim 16 , wherein the support includes a slot that is configured to receive a shaft that extends through a second side of the tailgate and the bracket. 
     
     
         18 . The vehicle assembly as recited in  claim 16 , wherein a drive rod extends through the support and the bell crank, and the bell crank includes a post that is attached the second end of the nitrogen gas strut. 
     
     
         19 . The vehicle assembly as recited in  claim 11 , wherein the second end of the nitrogen gas strut is above a vehicle bumper. 
     
     
         20 . The vehicle assembly as recited in  claim 11 , wherein the nitrogen gas strut is mounted in an open area defined by the second vehicle sidewall and an outer panel of a vehicle body.